Wireless mesh network

About: Wireless mesh network is a research topic. Over the lifetime, 13600 publications have been published within this topic receiving 221035 citations. The topic is also known as: WMN.

Scheduling Multiple Partially Overlapped Channels in Wireless Mesh Networks

Abstract: In this paper, we explore the use of partially overlapped channels in wireless mesh networks that consist of multiple 802.11-based access points. We propose novel channel allocation and link scheduling algorithms in the MAC layer to enhance network performance. Due to different traffic characteristics in multi-hop WMNs compared to those in one-hop 802.11 networks, we perform our optimization based on end-to-end flow requirement, instead of the sum of link capacity. In addition, we discuss other factors affecting the performance of POC, including topology, node density, and distribution.

Experiences with a Mobile Testbed

Abstract: This paper presents results from an eight-day network packet-trace of MosquitoNet. MosquitoNet allows users of laptop computers to switch seamlessly between a metropolitan-area wireless network and a wired network (10 Mbit/s Ethernet) available in offices and on-campus residences. Results include the amount of user mobility between the wired and wireless networks, the amount of mobility within the wireless network, an examination of application end-to-end delays, and an examination of overall packet loss and reordering in the wireless network. We find that the average mobile host switches between the wired and wireless networks 14 times during the trace and moves within the wireless network five times. Round trip latencies in the wireless network are very high, with a minimum of 0.2 seconds. Even higher end-to-end delays, of up to hundreds of seconds, are due to packet loss and reordering. These delays cause users to change their usage patterns when connected to the wireless network. We conclude that latency is a critical problem in the wireless network.

Wireless network synchronization

Abstract: Systems and methodologies are described that facilitate synchronizing timing among wireless nodes in a wireless communication network. A tracking wireless node can synchronize to a global positioning system (GPS) signal if available. Alternatively, the tracking wireless node can receive quality metrics related to one or more target nodes. The quality metrics can relate to parameters that can be utilized to evaluate the target node for timing synchronization. Based on the quality metrics, the tracking wireless node can select a target wireless node for timing synchronization. The tracking wireless node can subsequently synchronize timing with the target wireless node. In addition, the tracking wireless node can continually evaluate surrounding wireless nodes to detect whether other wireless nodes have higher quality metrics than the current target wireless nodes and can accordingly resynchronize with nodes having higher metrics.

FADE: Forwarding Assessment Based Detection of Collaborative Grey Hole Attacks in WMNs

Abstract: Data security, which is concerned with the confidentiality, integrity and availability of data, is still challenging the application of wireless mesh networks (WMNs). In this paper, we focus on a special type of denial-of-service attack, called selective forwarding or grey hole attack. When this attack is launched at the gateways of a WMN where data tend to aggregate, it could lead to severe damages due to loss of sensitive data. Most existing proposals that focus on detecting stand-alone attackers via channel overhearing are ineffective against collusive attackers. In this paper, we propose a forwarding assessment based detection (FADE) scheme to mitigate collaborative grey hole attacks. Specifically, FADE detects sophisticated attacks by means of forwarding assessments aided by two-hop acknowledgement monitoring. Moreover, FADE can coexist with contemporary link security techniques. We analyze the optimal detection threshold that minimizes the sum of false positive rate and false negative rate of FADE, considering the network dynamics due to degraded channel quality or medium access collisions. Extensive simulation results are presented to demonstrate the adaptability of FADE to network dynamics and its effectiveness in detecting collaborative grey hole attacks.

Channel allocation and routing in wireless mesh networks : A survey and qualitative comparison between schemes

Abstract: In order to avoid transmission's collisions and improve network performances in wireless mesh networks (WMNs), a reliable and efficient medium access control (MAC) protocol and a good channel allocation are needed. Allowing multiple channels use in the same network is often presented as a possible way to improve the network capacity. As IEEE 802.11, IEEE 802.15 and IEEE 802.16 standards provide more than one channel, thus a trivial way to improve the network performances is to allow transmission on multiple channels in each network node. A lot of research work have been conducted in the area of multi-channel allocation in order to improve the aggregate bandwidth of the hole network. In this paper, we focus our attention on the proposals for solving the channel allocation problem for Multi-Transceiver per node in the backbone level using the IEEE 802.11s technology. We classify these proposals into three categories. The first one consists on channel allocation proposals done at the MAC level independently to the other layers. The second one consists on a channel allocation approaches done by a modified MAC collaborating with upper layers. Finally, the third category concerns channel allocation methods implemented in a new layer resulting from a common-layer design between MAC and Network layer. For each category, the existing multi-channel protocols and their channel allocation approaches are identified. A qualitative comparison is conducted according to the advantages that they present, the limitations and problems they are facing, and the performances they are claiming to offer.